Had unit running for 3 days straight, all of sudden motorhome got warm. I could tell the compressor wasn't on. Switched it from high ac back to high fan. Fan operates fine. Switch it back to low or high ac and it was a huge strain on system. My first thought was a capacitor went bad. Had two bad terminal s on the top of a black plastic round capacitor., which I am assuming is the compressor capacitor. There are also two other ones, on smaller metal round one and a oval shaped metal one. The black one has wires coming from the smaller metal one and wires from a small black box above it. I'm unsure of the electrical component that is the " black box". I put two new ends on the wires that were bad and the unit did the same thing at start up again. My question is how do you know when your compressor locks up? Is the strain so bad that this is the indication? I'm ok with replacing electrical components because it is the cheapest route, however if this sounds like a replacement to anyone I value your opinion. Please help!
The black plastic capacitor is the compressor start capacitor, it is only in the circuit until the compressor gets up to speed. The black box is the start relay, it stays closed until the compressor gets up to speed the opens taking the start capacitor out of the circuit. The wires should go from it to the small metal round capacitor and the black box.
You can Ohm out the start relay, it should be closed between Terminals 1 and 2 and the coil is from 2 to 5. You can also check the 2 capacitors, you need a Volt Ohm Meter that has a capacitor testing scale. The microFarads should be on the capacitors you will need to cut the bleed resistor on the start capacitor before testing it.
SOURCE: Compressor tries to kick in but then stops.
it is a hard start compacitor, the unit is not supposed to have three compacitors.
SOURCE: Coleman Mach 15 AC just quit. no compressor sound, no fan
If this is a ducted unit, check the thermostat. It has a fuse for protection that may have blown. If the fuse is fine and you have power to the upper units control box, check for 120V incoming power at the control box and also check for incoming 12V on the Yellow and GH wires when tstat is set to high cool.
Hope this helps.
At the compressor connectors you have a live and a neutral phase. The live usually goes to a ptc relay starting mechanism which you can test with a meter. If you can disconnect the relay and check the windings of the compressor from one pin to the other two it will tell you if the compressor is open circuit. It is more often than not an overload fault.
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